Remote Array Mapping

ABSTRACT

Electrical component location is provided. Employed location techniques may include providing a cycling signal, having components to be located sense the cycling signal at the same time, report back the sensed signal, and determining relative locations for one or more of the components using the sensed signals reported by the components.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional application62/634,254, which was filed on Feb. 23, 2018 and is entitled “RemoteArray Mapping.” The '254 application is incorporated by reference in itsentirety into this application.

BACKGROUND

Photovoltaic (PV) cells, commonly known as solar cells, are devices forconversion of solar radiation into electrical energy. Generally, solarradiation impinging on the surface of, and entering into, the substrateof a solar cell creates electron and hole pairs in the bulk of thesubstrate. The electron and hole pairs migrate to p-doped and n-dopedregions in the substrate, thereby creating a voltage differentialbetween the doped regions. The doped regions are connected to theconductive regions on the solar cell to direct an electrical currentfrom the cell to an external circuit. When PV cells are combined in anarray such as a PV module, the electrical energy collected from all ofthe PV cells can be combined in series and parallel arrangements toprovide power with a certain voltage and current.

PV modules are installed in a layout at an installation site. Theinstallation process involves an installer placing rows of PV modulesand connecting these rows of PV modules together into one or moregroupings of the installation layout. The PV modules may be connected ingroupings of various numbers and have several groupings at aninstallation site. The groupings may be uniform, for example six PVmodules in each grouping, and nonuniform, for example, four PV modulesin two groups and six PV modules in one group. Cabling and connectionsare also installed by an installer to connect and support the PV modulesof a grouping and for the PV system installation as a whole. Oncefinished, the cabling and connections for the groupings of the PVmodules, and of the PV system installation, remain in place, to permitthe PV modules, and the whole installation, to transmit the electricalpower the system is generating.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a location testing module as may be employed tolocate components connected in one or more groups, according to someembodiments.

FIG. 2 illustrates a process for locating components in one or moregroups, according to some embodiments.

FIG. 3 illustrates a PV Module system, according to some embodiments.

FIG. 4 illustrates a PV Module with daisy chain connections, accordingto some embodiments.

FIG. 5 illustrates a microinverter output stage, according to someembodiments.

FIG. 6 illustrates a schematic of branch cable segments and associatedimpedances, according to some embodiments.

FIGS. 7 illustrates an accumulation of a branch circuit network andassociated impedances, according to some embodiments.

FIG. 8 illustrates topology from an inactive microinverter functioningas a peak detector, according to some embodiments.

FIG. 9 illustrates a schematic of a two-branch system having variousassociated impedances and active/inactive microinverters, according tosome embodiments.

FIG. 10 illustrates a computing system and network, which may beemployed for locating components connected in one or more groups,according to some embodiments.

FIG. 11 shows a two branch AC module system and an exemplary topologysetup of a PLC module according to some embodiments.

FIG. 12 shows a process for gathering data for use in a branch detectionscheme according to some embodiments.

FIG. 13 shows frequency sweep results as may be encountered according tosome embodiments.

FIG. 14 shows reverse frequency sweep results as may be encounteredaccording to some embodiments.

FIG. 15 shows merged frequency sweep results as may be encounteredaccording to some embodiments.

FIG. 16 shows data from a frequency sweep shown as discrete points asmay be encountered according to some embodiments.

FIG. 17 shows standard deviation-based scoring comparing combinationscoring v. combination indexing as may be encountered according to someembodiments.

FIG. 18 shows a constructed frequency sweep, with the signal generatorin position L, of FIG. 3 according to some embodiments.

FIG. 19 shows standard deviation-based scoring comparing combinationscoring v. combination indexing as may be encountered according to someembodiments.

FIG. 20 shows three tables of data that may be gathered during processesaccording to some embodiments.

DETAILED DESCRIPTION

The following detailed description is merely illustrative in nature andis not intended to limit the embodiments of the subject matter of theapplication or uses of such embodiments. As used herein, the word“exemplary” means “serving as an example, instance, or illustration.”Any implementation described herein as exemplary is not necessarily tobe construed as preferred or advantageous over other implementations.Furthermore, there is no intention to be bound by any expressed orimplied theory presented in the preceding technical field, background,or the following detailed description.

This specification includes references to “one embodiment” or “anembodiment” or “some embodiments.” The appearances of the phrases “inone embodiment” or “in an embodiment” or “some embodiments” do notnecessarily refer to the same embodiment. Particular features,structures, or characteristics may be combined in any suitable mannerconsistent with this disclosure.

Terminology. The following paragraphs provide definitions and/or contextfor terms found in this disclosure (including the appended claims):

“Comprising.” This term is open-ended. As used in the appended claims,this term does not foreclose additional structure or steps.

“Configured To.” Various units or components may be described or claimedas “configured to” perform a task or tasks. In such contexts,“configured to” is used to connote structure by indicating that theunits/components include structure that performs those task or tasksduring operation. As such, the unit/component can be said to beconfigured to perform the task even when the specified unit/component isnot currently operational (e.g., is not on/active). Reciting that aunit/circuit/component is “configured to” perform one or more tasks isexpressly intended not to invoke 35 U.S.C. § 112, sixth paragraph, or 35U.S.C. § 112(f) for that unit/component.

“First,” “Second,” etc. As used herein, these terms are used as labelsfor nouns that they precede, and do not imply any type of ordering(e.g., spatial, temporal, logical, etc.). For example, reference to a“first” PV module or other component does not necessarily imply thatthis PV module or other component is the first module or component in asequence; instead the term “first” is used to differentiate this PVmodule or component from another PV module or component (e.g., a“second” PV module).

“Based On.” As used herein, this term is used to describe one or morefactors that affect a determination. This term does not forecloseadditional factors that may affect a determination. That is, adetermination may be solely based on those factors or based, at least inpart, on those factors. Consider the phrase “determine A based on B.”While B may be a factor that affects the determination of A, such aphrase does not foreclose the determination of A from also being basedon C. In other instances, A may be determined based solely on B.

“Coupled”—The following description refers to elements or nodes orfeatures being “coupled” together. As used herein, unless expresslystated otherwise, “coupled” means that one element/node/feature isdirectly or indirectly joined to (or directly or indirectly communicateswith) another element/node/feature, and not necessarily mechanically.

“Inhibit”—As used herein, inhibit is used to describe a reducing orminimizing effect. When a component or feature is described asinhibiting an action, motion, or condition it may completely prevent theresult or outcome or future state completely. Additionally, “inhibit”can also refer to a reduction or lessening of the outcome, performance,and/or effect which might otherwise occur. Accordingly, when acomponent, element, or feature is referred to as inhibiting a result orstate, it need not completely prevent or eliminate the result or state.

In addition, certain terminology may also be used in the followingdescription for the purpose of reference only, and thus are not intendedto be limiting. For example, terms such as “upper”, “lower”, “above”,and “below” refer to directions in the drawings to which reference ismade. Terms such as “front”, “back”, “rear”, “side”, “outboard”, and“inboard” describe the orientation and/or location of portions of thecomponent within a consistent but arbitrary frame of reference which ismade clear by reference to the text and the associated drawingsdescribing the component under discussion. Such terminology may includethe words specifically mentioned above, derivatives thereof, and wordsof similar import.

In the following description, numerous specific details are set forth,such as specific operations, in order to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to one skilled in the art that embodiments of the presentdisclosure may be practiced without these specific details. In otherinstances, well-known techniques are not described in detail in order tonot unnecessarily obscure embodiments of the present disclosure.

This specification describes systems, process, and articles ofmanufacture involving mapping locations of electrical devices connectedin array configuration. The array of devices being mapped may be asingle branch of connected devices as well as a plurality of branchesconnected via one or more connecting nodes. Exemplary explanations,which include PV modules and microinverters, follow. Permutations oneach example may also be considered and some are provided, while stillmore are possible.

Turning now to FIG. 1, it illustrates a schematic of a location testingmodule as may be employed to locate components in one or more groups,according to some embodiments. Labelled in FIG. 1 are the systemtopology 100, location testing module (LTM) 110, external system 140,junction 150, cabling 191-93, test signal generator 120, sensors151-155, junction 130, wired components 161-163 through 16 n, wiredcomponents 171-173, and wired components 181-187.

In embodiments, the location testing module 110 may be configured todetermine the location of one or more wired components. These wiredcomponents may be connected in parallel into groupings as shown inFIG. 1. There may be different numbers of components in each groupingand the components may be identical to one another, have similartopologies but not be identical, have the same or different function,and may have other variances as well. While the LTM 110 is shown apartfrom each of the components to be located, in embodiments, an LTM may belocated in one or more of the components as well, the LTM may also be ahandheld device that may be pluggable for direct or remote systemtesting. The junction 150 may serve to monitor connection or otherstatus of the external system 140. The junction 150 may also serve tocouple and decouple the remainder of the topology shown in FIG. 1 fromthe external system 140. The junction may also serve a sensing functionto provide voltages, currents, frequencies, or other measurementsassociated with electrical exchanges to and from the external system140.

In operation, the LTM 110 may coordinate testing at one or more of thecomponents to determine the relative position of the tested componentsto other components in the group and the location as between groups aswell. This testing may include having components locally sample avoltage, current, frequency, or other variable at a planned instant oftime or during some narrow range of time and then determining, usingthese samples, the relative position of one or more of the components.The testing may also include using different voltages, currents andfrequencies as part of a testing protocol. To coordinate sampling, analert may be sent by the LTM 110 to have one or more of the componentsauto-sample at a target time or period of time. During this target timeor period of time the junction may decouple the external system 140 andthe test signal generator 120 may send a test signal to the componentsover cabling 191, 192, 193, and 194. The test signal may be sent tofewer than all of the cabling past the junction 130 if, for example,only one of the groups of components is being tested.

At the predetermined time or period of time, each component may measurethe received signal and report subsequently report the signal valuemeasured by that particular component. The LTM 110 may use thesemeasured signals to determine the relative position of components in agroup, whether a component is in a first group, a second group, or astill different group, etc. and for other reasons as well. The LTM maymake these determinations by comparing observed values measured andranking the observed measured values. Components reporting valuesfalling within a first range may be considered to be in a firstgrouping, components reporting values falling within a second range maybe considered to be in a second grouping, etc. Also, within rangescomponents may be further ranked as being closer or further from thejunction 130 or other device depending upon the observed and reportedvalue measured during the target time period.

Sensors 151, 152, 153, 154, and 155 may also be employed to verifyreported values from the components, to provide relative objectivereadings, and for other reasons as well, such as determining the statusof the cabling connected to the components being located. The componentsin a grouping are preferably connected to each other in parallel. Thesegroupings may share a junction 130 or use other topologies as well. Inembodiments, therefore, when an external system is decoupled orotherwise determined to be inactive, an LTM 110 may operate to determinethe grouping of a wired component, the relative position of componentsin a grouping, and report these findings outside the local system forvarious uses, including verification of system construction,versification of system operation, and for other reasons as well.

In embodiments, if a first round or subsequent round of testing isinconclusive or wants to be made more accurate, the LTM may adjust oneor more of: testing voltages, testing currents or testing frequencies inorder to hone in on appropriate testing delineations to identify groupsapart from other groups of components being tested, to locate individualcomponents relative to other individual components, and for otherreasons as well.

Turning now to FIG. 2, a flow chart illustrating a method, according tosome embodiments, for detecting locations of grouped components isshown. The method of FIG. 2 can include additional (or fewer) blocksthan illustrated. For example, in some embodiments, acknowledging therange of time at block 225 may not be performed or may also (or instead)be performed before block 260. As shown at block 200, a calibrationcycle may be initiated by a device performing functions of a locationtesting module. When cabling connecting components serves multiplepurposes, e.g., testing and power transmission, a dormant state may beconfirmed by the device performing LTM services. System line disconnectmay also be confirmed, as shown at block 210. Block 220 shows that aconfirmation signal may be sent to the components to be located. Thisconfirmation may be authorized or initiated by an LTM and may serve toconfirm that components being located will listen for a test signal at acertain instant or time period. Block 225 shows that components to belocated may affirmatively recognize receipt of the instructions tosample and also acknowledge the actual range of time in which thesampling will occur for the component. This, may, for example, be timedusing clock cycles as well as other timing methodologies. Block 230shows the LTM or device performing its functions may broadcast a testsignal for receipt by components to be located. As shown at Block 240,components listening for the broadcast signal may sense a voltage,current, frequency, or other variable during the test time period orinstant. At Block 250, these components may then report the testedvariable back to the LTM, to a central location for saving, combinationsthereof, and to other locations as well. Upon review of the reportedsensed values, the LTM may determine relative locations of one or morecomponents as well which grouping certain components are expected to befound. The relative grouping may be determined by observed voltages in afirst range, where all modules reporting voltages in the first range maybe considered to be in a first group. Then, relative position within agroup may be determined by ranking the reported values highest tolowest, lowest to highest, or some other suitable chronological order.This ordering may serve to describe the relative position within a groupfor a certain component. E.g., because component d reported an observedvoltage of 0.0034V and component r reported an observed voltage of0.0039 V, component d may be considered to be further away from the LTMthan component r.

Once determinations are performed, if acceptable results are reached,the calibration cycle may be started again and if unacceptable resultsare reached the process may cycle back to Block 220 and perform stepssubsequent thereto. Adjustments may also be made before, during, andafter iterative test cycles. For example, if a first round or subsequentround of testing is inconclusive or wants to be made more accurate, theLTM may adjust one or more of testing voltages, testing currents ortesting frequencies during performance of block 230 or at other times aswell, in order to hone in on appropriate testing delineations toidentify groups apart from other groups of components being tested, tolocate individual components relative to other individual components,and for other reasons as well. Thus, a first iterative test may beperformed at a first voltage frequency, the frequency may be adjustedfor a second round of testing, and the results compared to determineaccuracy of the iterative tests as well as the possible need for testingat third frequency or voltage or current or other variable. Byperforming multiple iterative testing, the LTM may identify a preferredtesting setup for the topology being tested. Thus, if one or morecomponents goes offline or otherwise changes the order of a grouping,the optimized testing settings from earlier tests may be used by the LTMto determine which component is malfunctioning as well as if thegroupings have changed in some way, e.g., the addition of anothercomponent in a grouping, the addition of a new grouping, and the removalof a grouping.

FIG. 3 illustrates an alternating current PV Module system 300,according to some embodiments. In a system of PV Modules e.g., 360 and370, wherein the modules comprise local inverters for converting the DCvoltage from the PV panel to an alternating voltage, the modules aredistributed among one or more branch circuits 310 and 311 as shown inFIG. 3. In this example, each of the two branches contains 12alternating current PV Modules, labeled A-L and M-X, respectively. Themodules typically have one of two types of connections to the branchcircuit. As shown, a “trunk” system is employed, where in a main cableis the trunk and each PV Module has a dongle to connect to the trunk. Atthe end of each trunk there is an end cap 320 to protect the end of thecable. Other connection techniques, linking the PV Modules to eachother, may also be employed. These connection techniques include a“daisy-chain” method, where a dongle and trunk connection are embodiedwithin the PV Module's microinverter and the microinverter itself hastwo ends of the AC cable coming out, each with its own connector. Thisdaisy chain connection technique is shown in FIG. 4. Thus, multipledaisy-chain microinverters can be strung together to build a branchcircuit 310 and 320, also typically requiring an end cap 320 on the“last” module in the branch to close off the normally exposedconnection.

In both connection techniques, the “first” PV Module (L or X in FIG. 3)must interface ultimately to the subpanel 340 shown. To accomplish this,a “whip” cable 350 to adapt each branch circuit connectors to bare wiresor other connectors, may be employed. In embodiments, the whip cablesmay have a mating connector on one end and stripped/exposed wires on theother.

After the whip cable 350, in embodiments, AC wires may extend from therooftop (typically a roof, though maybe any mounting surface somedistance from the subpanel) to the subpanel 340. Embodiments may employ“drop” cables 330, which are shown in FIG. 3. The breaks in the linesshown in FIG. 3 indicate that a comparatively long distance may betraversed by the drop cable 330. For example, the module-to-moduleconnections may be a few feet in length, but the drop length may be 50feet or significantly more in length. To connect the whip cable to thedrop cable, embodiments may employ a transition box, which may include asmall electrical chassis that houses the splices between the whip anddrop cable. Alternatively, the whip and drop cables may be fully“connector-ized” so that no transition box is necessary. Indeed, inembodiments, the whip cable 350 itself may actually be long enough toserve the purpose of the drop cable as well. Also, one may stringtogether several connector-ized drop/whip cables to achieve whateverdesired length.

The drop cable, which may be housed in a conduit that may not benecessary for each branch circuit, depending on the cable design, isshown as terminating into a subpanel through circuit breakers 341. Thissubpanel may be called an aggregation or “agg” panel. The subpanelcombines the current from the branch circuits through the bus bars 342as shown and provides a larger breaker 343 to the main service panel. Inembodiments, if the wires are housed in proper conduits, it may not benecessary to provide very large breakers, though it is probablyconsidered good practice to provide a safety margin when sizing thesebreakers.

Also attached to the subpanel is a gateway device, or PV Supervisor 380.This gateway device 380 may be connected via a breaker and be equippedwith powerline carrier (PLC) communication capability so that it maycommunicate electrically with the PV Modules. Other communicationtechniques, such as wireless or dedicated wires are also possible.

The entire system of FIG. 3, may be disconnected from the main powergrid via the large breaker 343 to the main panel, or via a breaker inthe main panel itself. In embodiments, during testing, the AC lines maynot be energized, but the gateway device 380 may still be powered via adedicated source (such as a power outlet or battery). As such,communication while the PV Modules are not connected to the grid ispossible, assuming the PV Modules have sufficient sunlight or othersource of power.

In embodiments, the gateway device 380 may be housed with the subpanel340 to form a single unit. This combined approach may allow fewercircuit breakers and the addition of other circuitry, such asswitches/relays, sensing, and another signal circuitry.

In embodiments, an installer or owner of a PV module system may desireto know the exact electrical schematic (or “map”) of the system 300. Forexample, as shown in FIG. 3, module A connects to B and B to C and soforth. Each module would have a unique identifier (e.g., serial number).It is useful for maintenance, troubleshooting, and system monitoring toknow the interconnectivity of the modules. Furthermore, it may also beuseful to confirm that no more than an allowed number of modules are onany one branch circuit. For example, breaker ratings may serve to limitthe number of microinverters on a branch circuit. For example, 12modules per 20-A (rated) branch circuit may be allowed by the NationalElectric Code, due to a 320 W rating for each module. Consequently,embodiments may be employed that confirm the maximum number of PVmodules for a branch circuit have not been exceeded. Moreover, a correctnumber of installed PV modules for each branch circuit may also beverified in embodiments. Thus, consistent with the above descriptions,embodiments may use the physical characteristics of alternating currentPV Module microinverters and the branch circuit wiring for purposes oflocating AC PV modules in an array.

Consistent and different cycling voltages may be used as test signals inembodiments. These test signals may be generated in various locations inembodiments. These can include with the LTM in a centralized controller,as a stand-alone unit, and as part of one or more of the components tobe located.

FIG. 5 provides a high-level schematic of the output stage of a typicalmicroinverter, which may be used in embodiments as a test signalgenerator. This schematic is illustrative and does not limit the variousother circuit topologies that may be employed as a test signalgenerator. FIG. 5 shows a portion of an inverter circuit 500. Theportion 500 represents an output stage topology and has a bridge stage(H-bridge) 510 with four power MOSFETs 540, whose built-in diodes areshown explicitly. Naturally, these MOSFETs can be a variety of othersemiconductor devices, but it is assumed that whatever device they maybe, they have a diode function as shown. The bridge connects to theoutput (initially the trunk or daisy chain cable, ultimately the ACgrid) via an output filter 520. This filter is configured to mitigatethe high frequency switching noise that is produced by the bridge. Or,in the case of a low-frequency bridge (like an “unfolding” bridge), thefilter may just serve to reduce the electromagnetic interference (EMI)and not specifically target the switching of the bridge. In any case,the output filter is typically a low-pass filter and can be in manyconfigurations, though a simple LCL “T-filter” is shown and may beemployed.

Also shown is a bulk capacitor 550 that provides a substantiallyconstant voltage to the bridge during normal inverter operation. Adischarge circuit 560 is also shown—this may be an explicit circuit orjust the parasitic resistance of the capacitor and other parallelcircuitry. In effect, the discharge circuit 560 will discharge the bulkcapacitor, usually slowly, in absence of a charging means. For example,when the microinverter has been inactive for some time, the bulkcapacitor voltage will typically be near zero volts.

Also shown is a current sense function 570, which may be a smallresistance coupled to an amplifier. This sensor may be used to monitor aproxy for the microinverter output current. It is possible to place thecurrent sense on other wires with similar effect. Voltage sensefunctionality may also be employed or employed instead of current sensefunctionality in embodiments.

FIG. 6 shows the impedance structure of a branch circuit to be tested inembodiments. FIG. 6 illustrates branch cable segment 610 impedances 630,according to some embodiments. In FIG. 6, an impedance, Z1, is used torepresent the impedance of a cable segment of either the trunk cable ordaisy-chain cable, as discussed above. Although shown as four equalimpedances, they could be somewhat different, though would likely besubstantially the same for a uniformly spaced array of identical PVmodules. Each PV Module microinverter or other component being locatedcontributes to the branch segment impedances as shown in FIG. 6. Insidethe larger array, the segments accumulate and ultimately attach to endcaps, and to the whip and drop cables as shown in FIG. 7.

FIGS. 7 is a schematic of an accumulation of a branch circuit network ofimpedances, according to some embodiments. As seen in FIG. 7, the endcap impedance 720 (if any) is included. Zwd 730 represents the combinedimpedance from the whip and drop cables. In embodiments, it may be thatZwd >>Z1, when the whip and drop cables are much longer such that thecable impedances in embodiments may be dominated by resistance andinductance in test signal frequency ranges of interest.

In embodiments, for branch circuits connected in parallel at thesubpanel bus bars, there is another network of impedances as shown inFIG. 7. For example, a given PV Module from a first branch has at leastthe impedances of two whip/drop cable lengths between it and another PVModule from a second branch.

In embodiments, when microinverter output stages are employed for testsignal generation, the microinverter may either operate as apassive/measurement device or as an active/signal generating device. Inthe active case, the microinverter output bridge (FIG. 5) may beoperated to switch at a given frequency to produce a voltage into theoutput filter. This operation coincides with what the bridge does innormal operation, except the switching frequency and duty cycle of theswitches is modulated to attempt to form a low-frequency (e.g., 60 Hz)sine wave, which may conform to a regulatory standard and may be perfector near perfect, as output current. In this approach, it is preferredthat the array is disconnected from the grid (as above, with largesubpanel breaker or corresponding main breaker open, or both) and thereis no requirement to produce a sine wave output. In this active mode,while disconnected from the grid, the microinverter bridge can serve toproduce a high frequency (e.g., 20 kHz) square wave and provide that tothe left terminals of the output bridge. The amplitude of the squarewave will be equal to the bulk capacitor voltage. Therefore, there maybe sufficient power available from an input stage (not shown) to chargethe bulk capacitor and to produce this square wave.

In embodiments, very little power should be consumed, as the load willbe simply the collection of branch and microinverter impedances, whichcollectively have a high impedance. It is preferred that the bulkcapacitor voltage not be too high (such as 20 V) so as not to create ashock hazard and not also be too low (such as below 1 V) so that somesignificant voltage can reach other microinverters through the branchimpedances, which can attenuate the voltage more the farther they arefrom the source.

In embodiments it is preferred that the frequency of the activemicroinverter should be high enough so that the Z1 and Zwd aresignificant but not so high that the output filter substantiallyattenuates the bridge output voltage. In embodiments, 20 kHz may bebelow the cut-off frequency of the output filter of the microinverteryet high enough to observe significant impedance in the branch circuit.Other frequencies and frequencies with alternating voltages as well asvoltages that do not switch back and forth from positive to negative mayalso be employed.

The remaining microinverters may be kept inactive, meaning that they arenot actively switching their output bridge to generate a test signal.They preferably, provided enough power is available from the sun orother source, may be “awake” and capable of communicating and makinginternal measurements.

In embodiments, an inactive microinverter can appear to the branchcircuit as little more than a full-wave rectifier. As is shown in FIG.8, with the bridge switches off, four diodes remain and the circuit ofFIG. 8 forms a simple filter plus full-bridge rectifier. In use, ACvoltage present at the output of the microinverter in some embodimentscan pass through the output filter and be rectified into the bulkcapacitor (provided the voltage is sufficient to overcome the forwarddrops of the diodes once it reaches the bridge outputs). As such, byactivating a given microinverter in the array to produce ahigh-frequency AC signal, the bulk capacitors of other microinverterscan charge to a substantially DC level.

FIG. 8 also illustrates an inactive microinverter functioning as a peakdetector, according to some embodiments. The inactive microinverter inFIG. 8 has MOSFETs that have been removed to illustrate that they areeffectively open circuits with only their diodes 840 remaining. Theremaining circuit, with these inactive switches, functions as a peakdetector circuit, which can approximately detect the peak of the voltageat the microinverter output, which is shown at the right end of theoutput filter 520. More precisely, the voltage at the microinverteroutput may attenuate slightly through the output filter and be providedat the (former) output of the bridge circuit, which is now functioningin reverse as a rectifier. In embodiments, the rectifier can subtracttwo diode drops from the peak of this voltage and provide it to the bulkcapacitor, which will remain at a substantially DC level (assuming thedischarge circuit is discharging at a low rate). As this peak detectingprocess occurs, the voltage Vbulk becomes non-zero and some currentflows through the current sensor. While this current can be used as partof the mapping process, the changes in Vbulk may also be sensed and maybe more differentiated.

FIG. 9 is a schematic of a two-branch system as viewed via impedancesand active/inactive microinverters, according to some embodiments. Asshown in FIG. 9, two branch circuits 920, 921 come together at thesubpanel through their respective breakers. The ends of their dropcables are effectively connected in parallel via breakers, wires, andbus bars. In FIG. 9, for sake of example, we have assumed that allmicroinverters are inactive, as explained above, except formicroinverter W, which is active, also as explained above. Eachmicroinverter is show outputting a bulk voltage, such as Vbulk A, VbulkB, etc.

From this diagram, one can see that the voltage provided by W, in thistopology, will be received at the terminals of each microinverter by acomplicated parallel/series network of impedances. As such, the bulkvoltage measurements will likely be different (within measurementaccuracy) as long as impedances Z1 and Zwd are significant enough at thefrequency in question (e.g., 20 kHz).

The above describes how a microinverter can be used to generate a signalresulting differing bulk voltages in the other microinverters. Asubsequent step is to use this data to map the array. In one approach, amicroinverter, via software running in a gateway or system controller,or a microinverter itself, may be selected or may self-select. As such,the gateway or system controller or microinverter has already“discovered” the microinverters and recorded their serial numbers (whichwe simplify as letters: A, B, . . . etc.). Choosing any of thesemicroinverters, such as W in this example, the gateway or systemcontroller may send a signal to W instructing it to produce a testvoltage from its output bridge (e.g., 20 V at 20 kHz, or other suitablecombination). After waiting a short time, the gateway or systemcontroller or microinverter may then poll all the microinverter(including W) to report their bulk voltages. Since polling can take timeand the voltages may drift slightly, it is advisable for the gateway orsystem controller or lead microinverter to first issue a “snap” signal,which is a broadcast message for each microinverter to simultaneouslytake a snapshot of its bulk voltage measurement and store for laterretrieval. In that case, the polling simply involves “picking off” thestored bus voltage measurements.

Once all measurements are retrieved, the bulk voltages can be sortedaccording to the value and serial number. In embodiments, the bulkvoltages may be clustered and somewhat more tightly grouped. In the caseof two branches, two clusters of voltages that are relatively closer mayeach be identified. In FIG. 3, for example, the 12 highest voltages maybe presumed to be from M-X and the 12 lowest voltages may be presumed tobe from A-L. This is due to the high impedance of Zwd, through whichcurrent must pass four times from W to any microinverter A-L. As such,via these clusters, embodiments can estimate that microinverters A-L arein one branch and microinverters M-X are in another branch. For purposesof determining that an allowed number of microinverters, or less, are ina given branch, a testing cycle can be finished as this can bedetermined simply by counting the number of units in each cluster.

The process can be further refined to attempt to identify the clustersmore clearly or to identify the actual connectivity of frommicroinverter to microinverter by applying successive test voltages.After instructing W, for example, to apply a test voltage and pollingthe measurements, the gateway or system controller can then instruct Wto remove its voltage. At this juncture, the bulk voltages willdischarge through their discharge circuits, which may take seconds orlonger. As an improvement, the microinverters could be equipped with aspecial command to almost instantly discharge their bulk voltages viaturning on internal loads or briefly shorting out the capacitors via theMOSFET switches, or other suitable means.

After the system has returned to an inactive, zero voltage state,another microinverter can be activated with a test voltage and theprocess above repeated. The gateway or system controller can thencluster the voltages and may determine that all the same microinvertersare on the same branch circuit. If not, then more measurements arerequired to identify the branch circuits more confidently. If so, thenthe patterns in voltage can again be analyzed for patterns that mayindicate the particular arrangement of microinverters. In this case,since a first microinverter is mostly closely connected to the subpanelin Branch 2, by circuit analysis each of the voltages M-W should belower than X. These reported values would clearly identify X as theclosest microinverter to the subpanel. The remaining voltages, M-W,would be ordered from greatest to least to confirm their order is indeedX, W, V, U, . . . , M, from subpanel to end cap, as depicted in FIG. 3.

Likewise, multiple test voltage and measurement cycles can be repeatedto confirm that the estimated ordering is correct, proceedingsystematically through both branch circuits. Embodiments may employiterative algorithms for more efficiently and reliably obtaining theelectrical map of the array.

There may be selective considerations of topologies in embodiments.First, for certain frequencies and combinations of inverters anddrop/whip cable lengths, significant resonances may develop. In such acase, the bulk voltages may not increase or decrease monotonically alongthe chain of microinverters. To combat this, embodiments may employmultiple frequencies to be tested to work towards identifying suchbehavior. Second, it is possible that a more abnormal voltage appears,possibly identifying more clusters than branch circuits or otherunnatural behavior is reported back. Thus, sampling, reporting, andanalysis may indicate a flaw in the branch wiring, such as a shortcircuit or poorly latched connector. Embodiments, may, therefore,generate an error code in such situations and instruct the installer orother user to inspect the wiring before proceeding or whenever thetesting occurred.

In embodiments, it is possible to utilize additional circuitry in thegateway as a signal generator. That is, the gateway could impose a givenvoltage and frequency on the line with the microinverters inactive. Anadvantage to this approach is that the electrical location of thegateway is known, so that the gateway or system controller may have moreinformation on which to base estimates of electrical location ofmicroinverters. Such a technique may be combined with manual opening andclosing of breakers, or automated opening and closing of switches orrelays, to identify branches and connectivity of microinverters.Furthermore, the gateway or system controller may be equipped with itsown peak detector circuit so that the subpanel voltage could beconsidered in the voltage sorting schemes proposed above.

Still further, in embodiments, the signal generator may be a PLCcommunication circuit itself, which produces, inherently, a highfrequency sinusoidal signal coupled to the power line. In embodiments,the current sensor may also be employed using this methodology, howeverthe PLC circuitry is considered to be preferred due to inherentaccuracy. Likewise, a bulk voltage sensor may also be employed forsignal generation along with the PLC circuitry.

FIG. 10 illustrates a computing system and network, which may beemployed for locating components in one or more groups, according tosome embodiments. The PV System controller 1000 is shown with processingunit 1001, system memory 1002, a power interface 1003, a communicationinterface 1004, an I/O adapter 1005, a network adapter 1007, nonvolatilestorage 1006, and a bus 1008 connecting each of these components.Instructions stored on the system memory and nonvolatile storage 1006include operating systems, applications, modules, plug-ins, and data, asshown in block 1009. The PV System controller 1000 is shown connected tonetwork 1030 via communication pathway 1070 and connected to systemmanagement 1010 via communication pathway 1060. The network 1030 is alsoconnected to network resource 1040 and gateway 1080. The gateway 1080 isshown connected to system management 1010 and network resource 1040.Thus, the gateway may be networked to the system controller 1000 and notnecessarily in the same protective enclosure. The communication pathways1060 may be secure pathways, such as VPNs or other private channels. Thecommunication pathways 1070 may be public communication links such asthe Internet as well as local intranet topologies.

In use, the PVS controller 1000 may manage and carry-out the locationtechniques described herein and report its results to system managementmodule 1010. This system management module may be at the PV installationas well as remote from the PV installation, for example at a completelydifferent installation site or a remote command center. The module 1010may provide instructions to the PVS controller before during and aftertesting and may provide other functionality as well. The systemmanagement module may rely on other resources to determine a course ofaction after receiving location reports or analysis. These resources mayinclude maintenance services, diagnostic services, and other services aswell. Thus, in embodiments, the PVS controller may carry out thelocation services with and without assistance from external sources andthis assistance may include instructions for testing schedules,instructions for mitigation schedules, and troubleshooting assistance.

Thus, embodiments can employ various techniques to map clusters of ACmodules or other power electronics that are separated by long lengths ofAC cabling. As noted, various mapping processes and techniques andconfigurations may be employed when seeking to map power electronics,such as AC modules, positioned in one or more arrays.

An exemplary two-branch setup with twenty-four total microinverters isidentified above and used in an example below. The disclosed embodimentsmay be used for mapping other configurations and electronic devices aswell. For example, systems with fewer or more microinverters and feweror more branch circuits can also be evaluated, and the electronicdevices may be other power electronics, as well as electronics notconfigured for generation or conversion of power, but instead havingother circuit topologies upon which a background voltage can be measuredand repeated testing and monitoring as described herein can beperformed.

Exemplary techniques may employ some or all of the previous as well asthe following processes. Characteristics of a known power electroniccircuit, a circuit such as in FIG. 1, or otherwise, may be relied uponduring testing for purposes of locating the relative position of devicesin which these known circuit topologies reside. For example, inembodiments the topology and specific sizes or other characteristics ofa known LC output filter, such as 520 in FIG. 5, may be relied upon forpurposes of testing, interpreting test results, and ultimately locatingthe electrical device with the LC filter, such as a microinverter, in anarray of other electrical devices having the same LC filter or anotherknown circuit with known electrical attributes. For example, inembodiments, as discussed in FIG. 12, multiple measurements of voltageor another measurable electrical attribute may be conducted over aseries of frequencies for the devices to be located in the array.Resulting measured voltages or other electrical attributes may becollected and compared to each other to identify relative differences inorder to reach conclusions as to the relative positions of the powerconverters or other devices in the one or more arrays being mapped.Conclusions as to groupings, e.g., branch location, may be a primarypurpose of the mapping embodiments described herein.

Preparations ahead of a multiple frequency measurement, i.e., sweeptesting, of devices to be mapped may be performed. These earlypreparations may include isolating the devices prior to comparinginduction loses experienced through AC cabling connecting the powerconverters or other electrical devices that can be used for mappingpurposes. This device isolation may require testing for and makingadjustments for manufacturing tolerances and transient voltages of theLC circuit, or other known reference circuit, to be compared betweenpower converters or other electrical devices. Device isolation may beconducted at the initial testing as well as at intervals during afrequency sweep to confirm or reconfirm the adjustments determined forthe circuits of the devices being mapped. Device isolation may beaccomplished by minimizing unwanted transient voltages in the circuitsto be tested. These unwanted transient voltages may be minimized throughsynchronized capacitor discharge in each of the reference circuits ofthe devices to be mapped. A controller, for example may send out aglobal instruction to each device to be mapped having them carry outspecific discharge instructions at a synchronized time certain in thefuture. When no capacitor is located in the known reference circuitother equalizing techniques may also be used. For example, a stablevoltage can be generated locally and measured at known intervals to setup a base-line reference that can be compared against. Other backgroundsetting techniques may also be employed depending upon the circuittopology. Once the transient voltages are reduced or adjusted for themapping techniques, using frequency sweeps or other reference techniquesmay be employed to identify groupings of the devices as well as theorder of these branch groupings.

FIG. 3 shows an exemplary 24 microinverter system that may be mappedusing the techniques and processes described herein. This 24microinverter system, may include SunPower's Gen-3.1 microinverters. Theexemplary tabular and graphical results provided in this applicationwere generated using SunPower's Gen-3.1 microinverters and the arraytopology of tested system is shown in FIGS. 3 and 11, where FIG. 11shows the effective topology when the switches of the main panel areclosed. Accordingly, when the breakers of FIG. 3 are in the “ON”position the circuit simplifies to FIG. 11. Other tabular and graphicalresults may result when different topologies are employed and whendifferent microinverters or other components are employed.

FIGS. 3 and 11 also show that an array may be mapped before it has beencommissioned, and therefore is not connected to the grid or to a mainpanel. If an array was already commissioned or otherwise connected tothe power grid, an isolation step would need to occur before mapping canbe completed. Various devices may be employed to carry out the mappingprocesses of embodiments. For example, as noted above, the gateway (PVS)may be conducting portions or all of the needed sweeping and listeningand other functionality described herein. In embodiments, a testingmodule may also be employed, as is shown in FIG. 11. This testing module(personal computer 1110 for example) may be locally employed as well asremotely employed, over a network remote from the gateway and the systembeing mapped. In FIG. 11 a PLC (power line communication) moduleconnected to a personal computer 1110 running python or other testingcontrol device is shown. Local testing may also be carried out by alocal controller at the gateway, the local testing module 1110, oranother local module. Remote testing may also be employed wherein arraymapping control signals may be sent to the PLC module for subsequentrelay to the devices of the array to be mapped. Other methods ofcommunication may also be employed. For example, low voltage wired andwireless communications may also be conducted in addition to or in lieuof power line communications between the devices being tested and thedevices conducting the testing and data gathering.

Embodiments may comprise none, one, or more than one of the aspectsdescribed herein when carrying out mapping processes, including todetermine the number of microinverters or other device of an arraybranch or other location of an array. As is shown in FIG. 12, forexample, at the outset, all microinverters or other devices may becommended to reset their reference circuits to be used in the mappingprocess to a known expected value. For instance, the bulk capacitor inthe LC circuit of FIG. 5 for each of the microinverters of the array tobe tested, may be commanded to be drained. This draining function may beactive for several seconds, e.g., 3, 4, and five seconds, to ensure thatany accumulated energy is dissipated or otherwise consumed.

In certain microinverters when the input is powered, a resident voltageof about 10 volts is present due to internal topology interconnection tothe bulk capacitor (a conductive path charges the bulk capacitor to avoltage similar to the house keeping supply voltage). This residentvoltage is intended to be discharged ahead of the testing and reportingof a baseline parameter to be reported by each of the devices beingmapped.

After receipt of the instruction or a request for a response, each ofthe microinverters or other devices to be located, observe and/ordetermine their “rest” voltage or other measured parameter and send thisbaseline attribute to the PVS or other controller conducting themapping. These discharge and reporting steps may be conducted at asynchronized time, such as the PVS sending a signal for concurrentdischarge or a time certain in the future for concurrent discharge.

During early steps, and perhaps next in some embodiments, one of thedevices to be mapped will be selected as a signal generator. The signalsgenerated by this generator may be set at different frequencies andbroadcast to all the devices being mapped whereby the changed electricalstate for each of the devices being mapped can be measured and thencompared to each other for purposes of locating the device on a certainbranch and for purposes of further locating the relative location ofeach device on that particular branch. This selection will remove theselected device from reporting the sweeping test results as the selecteddevice is generating the sweeping frequencies being received by theother devices being mapped and will not be in a position to receive andtest signals via the connecting network. This selection may beaccomplished by the PVS selecting a microinverter serial number atrandom to perform the function of a signal generator. This selection mayalso be made for a device whose location in the array is known. If sucha device is available, it is preferred that the device with the knownlocation be selected as the signal generator because fewer iterationswill be likely required to map the remaining devices.

In preferred embodiments, the signal generator may apply a 50%duty-cycle square wave at a fixed frequency with an amplitude of 50volts where the input converter of the signal generator microinvertermust regulate its dc bulk capacitor voltage to 50 volts. Other voltagesand duty cycles may also be employed. Once the sweeping frequency hasstabilized, the PVS or other controller may request all microinvertersor devices being mapped to measure their dc bulk capacitor voltage andreport it via PLC, or other communication method, back to the PVS,controller, or other device identified to listen for the reportedparameters. The PVS or other receiving device may record the observedvoltages or other observed parameters for the given test frequency.These received voltages or other parameters may be adjusted by thedevice or the receiving controller to account for the resting voltagemeasured earlier in the mapping process. For example, a known restingvoltage of 0.3 mV for device x may be deducted from an observed voltageof 3.0V for device x to yield a net observed voltage for device x. Thisadjustment may be conducted for each device to be mapped and at eachtest frequency in order to control for unique attributes of the variousdevices being mapped.

The test frequency may be changed and a second round of observations,reporting, and adjustments may be conducted. Repeated additional sweepsat different test frequencies may be conducted. These sweeps may be setat frequency intervals like those in FIGS. 13-16 as well as at otherintervals, e.g., 50 Hz, 100 Hz, 150 Hz, 250 Hz, 500 Hz, and intervalstherebetween as well as multiples (e.g., 2×, 3×, 4×, and 5×) thereof.Once all the desired sweeps are conducted and reporting is essentiallyor completely finished, the signal generator may be placed into apassive state and all the microinverters or other devices being mappedmay be commanded to drain their dc bulk capacitors as a reset. Next, thesignal generator microinverter may perform a second grouping offrequency sweeps of the arrayed devices being mapped, however this timethe frequency sweep may be performed in reverse order (highest frequencyfirst and lowest frequency last). Reporting of the measured voltages orother parameters may be reported and collected as above or below. Allthe microinverters or other devices may be put in a passive state andthe gathered data may be saved to a file for post processing. Themicroinverters or other devices being mapped may also be brought backonline once the reporting is completed and the analysis of the reporteddata is underway. When relative locations of the devices in the arrayare determined the controller or other location testing module, e.g. 110of FIG. 1, may store the data as well as report the locations outside tothe system and send the location data to each of the devices mapped bythe location testing module.

The reverse frequency sweep can serve to identify target circuits thatbehave differently at higher and lower frequencies. For example, thehigher frequencies may prevent complete capacitor discharge and may,therefore, not allow for accurate readings once not enough time fordischarge is allowed. Therefore, by conducting frequency sweeps in bothdirections, from high frequencies down and from low frequencies up,attributes of a circuit topology that become unmeasurable at high or lowfrequencies, i.e., capacitor charging and discharging, can be identifiedand discounted during the analysis phase of the mapping process.

Thus, a main capability of exemplary processes can be their ability toidentify clusters (e.g., of AC modules) separated by long lengths of accabling. While system configuration can vary from installation toinstallation, using installer or other configuration input, and postprocesses, the frequency sweep data can be employed to reveal correctclustering, and module to module schematic in embodiments. In somesystems embodiments may be carried out solely with firmware changes andwithout added hardware or modification of hardware in installed systems.

FIG. 12 shows a process for gathering data for use in a detection schemeaccording to some embodiments. As can be seen, once started (e.g., box1205), an early part of the process may include (e.g., box 1210)discharging each of the bulk capacitors of all microinverters in thesystem to be mapped. From there, a request (e.g., box 1220) may be sentto obtain the bulk capacitor voltage for each of the microinverters tobe mapped. These requested voltages may be stored (e.g., box 1230) asinitial measurements for each of the microinverter bulk capacitors. Arandom microinverter may then be selected (e.g., box 1240) to be thesignal generator and may be commanded to begin frequency sweeps usingchanging frequencies. Received voltages (e.g., box 1245) from eachmicroinverter may then be stored and rest voltages may be subtractedfrom the received voltages for each microinverter to calculate a “rest”voltage for the bulk capacitors. Frequency sweeps may then continueuntil complete (e.g., boxes 1247 and 1250). Once the frequency sweepingis complete the command signal generator may be placed in a passivestate (e.g., box 1255) and the bulk capacitors may be discharged (box1260) again. An opposite sweeping frequency may then be begun (e.g., box1265) and the “resting” voltages for this sweeping activity may becalculated and stored (e.g., box 1270). These frequency sweeps may thencontinue until complete (e.g., boxes 1273 and 1275) and once completethe signal generator may be placed in a passive state (e.g., box 1280)and the process may be ended (e.g., box 1285).

Exemplary Frequency Sweep Results

Table I of FIG. 20 shows how representative data, which may be generatedby the procedure of FIG. 12, and/or as described herein, may be storedby the location testing module 110 or elsewhere when conducting themultiple-frequency testing of embodiments.

As an example, the 24 microinverter set-up (configured with two 12microinverter branches) underwent the procedure in FIG. 12. PLCmonitoring tools were used to list all 24 serial numbers and thoseserial numbers were labeled MI 1 through MI 24. MI 1 was chosen to bethe signal generator. It is prudent to note that the physical locationof each MI (whether in branch 1 or branch 2) need not have a tie to thenumerical assignment given to each MI. However, in this exemplary setup,the location of the signal generator (MI1) was manageable and for thefirst set of results it was placed in position H as shown in FIG. 1 b.

An exemplary tabular representation of embodiments is shown at Table Iof FIG. 20. When data is gathered it may be graphed for purposes ofanalysis. Here, FIGS. 13 and 14 show graphed data for exemplary observedfrequency sweeps going from lowest to highest frequency (forward sweep)and a second data set going from highest to lowest frequency (backwardsweep).

Two or more sets of data were obtained in this example using thetopology of FIG. 3, FIG. 11, and FIG. 5, since the voltage measurementis taken at the dc bulk capacitor which is essentially part of a voltagepeak detect circuit. Given two data sets, the frequency sweep isapproximated finding the point by point minimum for each microinverterat each tested frequency. This selection of the minimum voltage at eachfrequency for each microinverter, whether sweeping from the lowfrequencies as in FIG. 13, which shows a forward frequency sweep with asignal generator in position H of FIG. 3, or sweeping from the highfrequencies, as in FIG. 14, which shows a backward frequency sweep withsignal generator in position H of FIG. 3, and the results in the dataplotted in FIG. 15, which shows a constructed frequency sweep with thesignal generator in position H of FIG. 3.

Analysis on the minimum voltages for a range of scanned frequencies foreach microinverters (were MI 1 is the signal generator in position H)may be conducted to determine microinverters of other devices belong towhich branch circuit, i.e. linear array. This analysis may include anunderstanding that microinverters or other devices being mapped willshare similar trajectories of voltage versus frequency. This sharedtrajectory, for microinverters of the same branch is shown in FIG. 15,where microinverters having solid lines belong to a first array andmicroinverters having a dashed line belong to a different array.

Visual inspection of FIG. 15 is consistent with this understanding asFIG. 15 reveals that the microinverters that share a branch circuit willhave similar trajectories. Accordingly, embodiments may employ processesthat can serve to detect shared trajectories and group them for purposesof revealing the members of each branch circuit.

While other techniques may also be employed when seeking to map thedevices, embodiments may examine the possible combinations of N (24)microinverters distributed among N (two) branches. Each combination maybe given a score that quantifies how tightly grouped its branches are.If all combinations are examined and scored, then a preferredexpectation in some embodiments may be that the combination with thelowest score will correspond to the correct physical grouping of themicroinverters. First, one combination may be considered (for example:branch 1 {MI2 , . . , MI12} branch 2 {MI13-M124}). Second, referring toFIG. 16, which shows data plotted as single points, the standarddeviation of “x's” at each frequency may be calculated and they may allbe summed to yield a single value. The same may be done for the “o's,”in order to yield a second value. Third, the two values may be summed toyield a single score for that combination. The process may be repeatedfor all possible combination yielding a score for each combination.

FIG. 17 plots the combination score of all 12-12 branch combinationswhen the signal generating microinverter is in position H. Table II ofFIG. 20 lists the scoring of all possible combinations. Row 12 showsthat the algorithm found the correct combination of MIs [2, 3, 9, 11,12, 13, 15, 16, 17, 19, 22, 23] for one branch and the second branchconsists of the MIs not listed on row 12. In fact, it is the lowestscore of all combinations ranging from 1-23 to 12-12.

The signal generator microinverter may be located in positions otherthan H of FIG. 3. However, additional mapping complexity may result. Forexample, it is more difficult to identify the branch members when thesource MI (MI1) is chosen to be in position L as shown in FIG. 11. Inthat case, visual inspection of the frequency response data (FIG. 18)reveals there is no clear break between the two branches as the dashedand solid lines have some overlap in FIG. 18, which shows a constructedfrequency sweep with the signal generator in position L of FIG. 3.Consequently, the location of the signal generator can impact the numberof iterations required to obtain a clear discrepancy between groupingsfor purposes of mapping the devices. Absent a clear break, a differentsignal generator may need to be selected such that a larger discrepancyexists between the branches being tested. If the number of branches isunknown, several different signal generators may need to be selecteduntil a clear demarcation is identified by the forward and backwardsweeping minimums.

Other techniques, such as a two-step approach may be used when a cleardemarcation is not identified by the forward and reverse sweep minimumsdiscussed above. For example, the standard deviation scheme may beapplied to score possible combinations and can result in scores that areclustered closer in magnitude (comparing FIG. 17 to FIG. 19). FIG. 19shows a standard deviation-based score for where signal generationsource is in position L of FIG. 3. Table III of FIG. 20 shows that forthis set of data, the lowest scored combination is not found in the 12throw as it was in Table II of FIG. 20. Therefore, to correctly identifythe branches, a standard-deviation based algorithm may need to beapplied to determine that the 12th row is the correct combination. Adata normalization scheme may be applied to assist in this instance aswell. Data normalization may also be used in other instances too.

Although specific embodiments have been described above, theseembodiments are not intended to limit the scope of the presentdisclosure, even where only a single embodiment is described withrespect to a particular feature. Examples of features provided in thedisclosure are intended to be illustrative rather than restrictiveunless stated otherwise. The above description is intended to cover suchalternatives, modifications, and equivalents as would be apparent to aperson skilled in the art having the benefit of this disclosure.

The scope of the present disclosure includes any feature or combinationof features disclosed herein (either explicitly or implicitly), or anygeneralization thereof, whether or not it mitigates any or all of theproblems addressed herein. Accordingly, new claims may be formulatedduring prosecution of this application (or an application claimingpriority thereto) to any such combination of features. In particular,with reference to the appended claims, features from dependent claimsmay be combined with those of the independent claims and features fromrespective independent claims may be combined in any appropriate mannerand not merely in the specific combinations enumerated in the appendedclaims.

What is claimed is:
 1. A system for mapping an array of electricalcomponents comprising: a plurality of electrical components, each of theelectrical components in the plurality distinct from each other, each ofthe electrical components spaced apart from each other, the electricalcomponents arranged in at least one array and connected to at least oneother electrical component; a frequency generator, the frequencygenerator configured to generate a frequency signal different from abase operating frequency, the frequency generator configured to send thesignal to each of the electrical components in the plurality; aplurality of sensors, each of the sensors of the plurality configured tomeasure, at the same time, a voltage or current at each of the pluralityof electrical components, the voltage or current reflecting theamplitude of the cycling frequency signal sent by the frequencygenerator and received at the electrical component being measured by thesensor; and a system analyzer configured to consider a plurality of thevoltages or currents measured by the sensors and attributable todifferent electrical components of the plurality and determine arelative position of electrical components with respect to otherelectrical components, wherein during a mapping cycle, the frequencygenerator generates frequency signals transmitted over the system in anascending frequency order and a descending frequency order, wherein thesystem analyzer considers responses to the frequency signals from eachof the electrical components, groups the electrical components accordingto shared trajectories of their responses, and assigns each electricalcomponent to a branch circuit based upon the groups.
 2. The system ofclaim 1 wherein each of the electrical components of the plurality arearranged in an array in parallel with each other and are connected viaat least one insulated wire.
 3. The system of claim 1 wherein eachelectrical component comprises a microinverter power train.
 4. Thesystem of claim 1 wherein the plurality includes eight or morecomponents in at least two one-dimensional arrays.
 5. The system ofclaim 1 wherein the frequency generator is located in one of theplurality of electrical components.
 6. The system of claim 1 wherein thefrequency generator is not located in one of the plurality of electricalcomponents.
 7. The system of claim 1 wherein the base operatingfrequency is 60 Hz of alternating voltages and wherein the frequencygenerator is further configured to generate the cycling frequency signalwhen the system is not connected to a mains power grid.
 8. The system ofclaim 1 wherein at least one of the electrical components is configuredto serve as the frequency generator and is further configured togenerate a frequency signal faster than 60 cycles per second, and isfurther configured to send a signal at the frequency generated, to eachof the other electrical components in the plurality.
 9. A process formapping an array of installed microinverters comprising: during a periodof disconnection from a mains power grid, generating a plurality of testsignals at frequencies greater than 60 cycles per second and sending thetest signals into an array of microinverters to be tested; for each testfrequency of the plurality, within a bracketed amount of time, at eachof the microinverters being tested, sensing a voltage or a currentgenerated from that microinverters receipt of the test signal; andreviewing the sensed value for each of the microinverters being testedand determining whether the tested microinverters are in the same arrayor in a different array, wherein determining includes identifyingvoltage minimums for each microinverter at each test frequency, groupingthe microinverters by the identified voltage minimums, and orderingmicroinverters of the same array by identified voltage minimums.
 10. Theprocess of claim 9 further comprising: determining the relative positionof each of the microinverters in the same array relative to each other.11. The process of claim 9 wherein the bracketed amount of time is 100milliseconds or less.
 12. The process of claim 9 wherein the test signalis generated by one of the microinverters.
 13. The process of claim 9wherein the test signal is a square wave and is generated by one of themicroinverters using a power train of the microinverter.
 14. The processof claim 9 wherein the test signal is generated by a photovoltaic systemcontroller, the system controller remote from the array ofmicroinverters and otherwise serving to monitor performance of the arrayof microinverters.
 15. A device for remote mapping of installedphotovoltaic modules comprising: a system controller for an array ofphotovoltaic (PV) modules, the PV modules located apart from the systemcontroller and arranged relative to each other in one or more arrays,wherein the system controller is configured to send a plurality ofascending and descending cycling test signal to each of the PV moduleswhen the PV modules are not generating AC for the mains grid, theascending test signals having frequencies increasing in step betweeneach cycle, and the descending test signals having frequenciesdescending in step between each test signal, wherein the systemcontroller is further configured to evaluate a sensed voltage or currentassociated with each of the PV modules, the sensed voltage or currentgenerated at the particular PV module and reflective of the cycling testsignal sent by the system controller, and wherein the system controlleris configured to determine whether each of the PV modules lie along thesame branch circuit.
 16. The device of claim 15 wherein the systemcontroller is further configured to use standard deviation analysis todetermine the relative position of each PV module on the same branchcircuit.
 17. The device of claim 15 further comprising: a gateway, thegateway configured to communicate evaluation results and for receipt oftesting instructions to be performed with regard to the PV modules. 18.The device of claim 15 wherein the cycling test signal is a square waveand has a frequency greater than 60 cycles per second.
 19. The device ofclaim 15 wherein the evaluation includes adjusting for impedances ofbranch circuits and drop lines between the system controller and the PVmodules being evaluated.
 20. The device of claim 15 wherein the systemcontroller is further configured to decouple the PV modules from a mainspower grid before sending the cycling test signal.